Bonding aluminium????
- Thread starter NozSpark
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still a lot of stress once the wind gets in there,
I'd deffo want it welded if it was my boat.
---------- Post Auto-Merged at 00:42 ---------- Previous post was made at 00:42 ----------
BTW,
loving the glitter pens,
I'd deffo want it welded if it was my boat.
---------- Post Auto-Merged at 00:42 ---------- Previous post was made at 00:42 ----------
BTW,
loving the glitter pens,
There are 3 stainless wires that run from the top of the mast, one down each side (you can just about see one of them) that is attached to the end of the spreader and one to the bow.
All the do is reduce flex in the mast, there is a socket and pins thatnhold it upright in the boat
---------- Post Auto-Merged at 00:51 ---------- Previous post was made at 00:50 ----------
The glitter pens are great aren't they
Ipad app!!
All the do is reduce flex in the mast, there is a socket and pins thatnhold it upright in the boat
---------- Post Auto-Merged at 00:51 ---------- Previous post was made at 00:50 ----------
The glitter pens are great aren't they
Ipad app!!
Right, unfortunately I didn't get any photos today but I can assure you that I will when I'm carrying out the repairs
I was at the club this evening and they had an inspection by some "big wig" sailing guy The mast repair was discussed with him and I mentioned about welding the plate,, he said that there wasn't a very good success rate with welded repairs... apparently masts are heat treated!!!!
He did say that a bonded and riveted plate would be the best repair, but that we would also have to be careful about electrolysis due to dissimilar metals (alloy mast & plate and steel pinned rivets)
So we're back to the original question (sort of), but with the additional electrolysis problem...
I was at the club this evening and they had an inspection by some "big wig" sailing guy
The mast repair was discussed with him and I mentioned about welding the plate,, he said that there wasn't a very good success rate with welded repairs... apparently masts are heat treated!!!!He did say that a bonded and riveted plate would be the best repair, but that we would also have to be careful about electrolysis due to dissimilar metals (alloy mast & plate and steel pinned rivets)
So we're back to the original question (sort of), but with the additional electrolysis problem...
dont use steel pinned rivets then
---------- Post Auto-Merged at 23:04 ---------- Previous post was made at 23:04 ----------
get a coded welder in and he will weld it and it will be fine,
---------- Post Auto-Merged at 23:04 ---------- Previous post was made at 23:04 ----------
get a coded welder in and he will weld it and it will be fine,
Steps,
The club will not go with a welded repair now that this guy told them it has a very poor success rate, so it'll HAVE to be a bonded and riveted repair now.
Otherwise it'll be another mast at knocking on
The club will not go with a welded repair now that this guy told them it has a very poor success rate, so it'll HAVE to be a bonded and riveted repair now.
Otherwise it'll be another mast at knocking on
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I can weld but I am certainly not a welder. My mate used to weld TVRs, I am embarassed to even let him see my welding! I did try to weld some Ali once, lots of unpleasantness, a loud sort od PFRUFFFFFFFFFFFFFT noise and a huge hole appeared from absolutely nowhere.
My welding is fine as long as you give it a few days to 'set'................. :coat
My welding is fine as long as you give it a few days to 'set'................. :coat
I understand Noz,
yet another numptie that hasnt got a clue,
wonder how all those cranes etc stay together, never mind motorcycles[cos thats what I know!]
I really really have no idea then as to what sort of bonding you would use to come remotely close to welding,
and if he has all these concerns about steel rivet pins, what alternative has he given you?
yet another numptie that hasnt got a clue,
wonder how all those cranes etc stay together, never mind motorcycles[cos thats what I know!]
I really really have no idea then as to what sort of bonding you would use to come remotely close to welding,
and if he has all these concerns about steel rivet pins, what alternative has he given you?
Steps,,
IIRC part of the Lotus Elise chassis is purely bonded together (not welded)
Many aircraft fuselage parts are bonded and not riveted or welded.
If you think about it, a bonded surface has got a much greater contact area than a weld
---------- Post Auto-Merged at 23:24 ---------- Previous post was made at 23:21 ----------
I've just had a look and all the pop rivet mandrels that I've seen are steel, no matter what the material of the rivet.
IIRC he said that they dip the rivets in something (adheive like) before they fit them.
IIRC part of the Lotus Elise chassis is purely bonded together (not welded)
Many aircraft fuselage parts are bonded and not riveted or welded.
If you think about it, a bonded surface has got a much greater contact area than a weld
---------- Post Auto-Merged at 23:24 ---------- Previous post was made at 23:21 ----------
I've just had a look and all the pop rivet mandrels that I've seen are steel, no matter what the material of the rivet.
IIRC he said that they dip the rivets in something (adheive like) before they fit them.
the problem with bond is it just goes, there is NO slack in it, its either stuck or its not!
perhaps you could just use liquid metal?
I have actually saw lots of weird and wonderful things stuck with that,
other than that I really dont know,
Im lost, speechless, and not often that happens, :C
perhaps you could just use liquid metal?
I have actually saw lots of weird and wonderful things stuck with that,
other than that I really dont know,
Im lost, speechless, and not often that happens, :C
You mean "evo stik liquid metal",,, if it does what it says then it sounds like just the right stuff for the job
The issue with the masts I suspect is that they are solution heat treated, then, the weld repair will screw up the metallurgy of the mast, just like welding hardened steel, or some variants of cast iron, or some variants of aluminium alloys!
The weld repair can be done effectively and correctly, however, if the mast is heat treated, then you would need to know the composition of the alloy from which it is made, then you would have to make the repair from compatible materials and following that you would need to re-heat treat the mast, a bit difficult I suspect, so the guy may know what he is talking about as the mast may not be aluminium, it may be an alloy, these are many and complex.
The weld repair can be done effectively and correctly, however, if the mast is heat treated, then you would need to know the composition of the alloy from which it is made, then you would have to make the repair from compatible materials and following that you would need to re-heat treat the mast, a bit difficult I suspect, so the guy may know what he is talking about as the mast may not be aluminium, it may be an alloy, these are many and complex.
so, its an aluminium alloy?
what about ally rivetted threads? and bolt a sleeve on?
though they may NOT be strong enough?!
perhaps alongside some liquid metal might work though......
what about ally rivetted threads? and bolt a sleeve on?
though they may NOT be strong enough?!
perhaps alongside some liquid metal might work though......
I think Sidey boy has hit the nail on the head there....
If the mast can be effectively repaired it'll save the club a lot of money, if it doesn't work then they are no worse off
If the mast can be effectively repaired it'll save the club a lot of money, if it doesn't work then they are no worse off
Well I did do metallurgy as part of my degree, and, it was part of my job in a past life!
One of my degree projects was to design and make, i.e. alloy up and cast, an aluminium alloy to withstand the greatest load possible from a selection of alloying elements and solution heat treat this to obtain the maximum tensile strength after machining to a specified dimension.
One of my degree projects was to design and make, i.e. alloy up and cast, an aluminium alloy to withstand the greatest load possible from a selection of alloying elements and solution heat treat this to obtain the maximum tensile strength after machining to a specified dimension.
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I was up the mast on my dads catamaran at the weekend fitting a stainless radar bracket which my dad made and welded up, which had to be fixed to an ally mast. Use monal rivets from a marine shop. Expensive but made for the job mate.
Hi all, Sidewinder is exactly right in his metallurgical comments, exactly right.
All kinds of things can happen!! For a start you would really need to know the exact composition of the parent metal before you chose a filler wire, as otherwise how are you going to know what the composition of the completed weld will be [you are making a kind of "metal soup"] and what its properties are going to be?
In general though, as long as you know "more or less" what type of aluminium alloy it is, this should not be TOO much of a problem, as there are welding wires that will cope with wide ranges of parent metals, but you will DEFINITELY need to know roughly what "group" of aluminium alloys it belongs to. For example, if it is a magnesium type alloy, as opposed to a aluminium/silicon one, because the the choice of consumables will be completely different. Trouble is there are loads of types and grades of aluminium...
As Sidewinder rightly says, it could very well be [and most likely is] a solution treated and precipitation hardened alloy [don't ask!!] but, if it is, unless you know exactly what the material is, and are able to re-heat treat it, you will end up with a softened/weakened area in the "heat affected zone" next to the weld. This MIGHT actually sort its self out, as SOME alloys "age" at room temperature, and harden/strengthen themselves, all by themselves!! over a few days, others need the heat treatment.
Once again, never mind the "heat affected zone" you have no idea what is going to happen to the weld itself, as unless you know the composition of the parent metal, the composition of the filler rod, and the degree of "dilution" in the weld pool [and are also a metallurgist] god only knows what the result will be!!
This is probably taking a very pessimistic view though, as aluminium alloys are welded every day with great success, but you will definitely have to know at least roughly what alloy it is..
As to welding sets..
You can oxy/acetylene weld aluminium, trouble is the flux is very corrosive and so you cannot do lap joints or fillets as you will not be able to remove all the flux residue and it will later on eat its way through the joint!!
You can MIG weld aluminium, but this is certainly not the way to go for repairs and is really only suitable for the fabrication of such things as tipper lorry bodies.
MIG power sources and TIG power sources by the way are COMPLETELY different. A TIG power source, is very much like a MMA [stick welding] one, in that it is a "constant current" powr source, and has what is called a "sloping characteristic"
This means that it is designed so that, as the welder, [the man doing the welding] lengthens or shortens the arc, although the volt drop across the arc will obviously change, the set does its best to maintain the same current, despite the change in the resistance across the arc gap.
A MIG power source is completely the reverse and is known as a "constant voltage" power source, with a "flat characteristic" This tries to do the opposite thing, and tries to keep the voltage constant, and the current can do as it likes!! Reason for this, is that with MIG, the welding set itself keeps the arc length constant. [it is termed a "semi automatic" process]
It does this by keeping the same voltage across the arc gap. If the gap shortens, the set will increase the current, the wire will melt off quicker, and the original arc length will be restored, and in the same way, if the arc length, well, lengthens! the set will reduce the current, the melting rate of the wire will reduce, and the arc length will once again return to "normal" THE WIRE SPEED REMAINS THE SAME. [With VERY rare exceptions]
In fact, the controls on the front of a MIG set have nothing at all to do with the current, they set the VOLTAGE [and hence the arc length and the "metal transfer mode" [don't ask!]
You actually set the CURRENT by means of the wire feed speed...
Back to TIG, this is, despite what everyone thinks, quite an easy process. If you can gas weld, you can TIG weld, it is as simple as that. Exactly the same technique, just the torch and rod angles are a bit different.
To TIG weld aluminium you need a set with an AC output. [Aluminium HAS been welded on DC in the past in highly specialised applications, but in general, NO CHANCE!!] You also really want "balance control" and "pulse" is nice too!
As to shielding gas, you will need in general, pure argon, [not cheap!] You CANNOT use the same stuff you would use for welding steel with your MIG set.
The main thing that is surprising when you try to weld the stuff though, is the sheer amount of heat that is required. Although aluminium melts at a low temperature, [about 600c??] it makes a great "heat sink" and to weld stuff only about 1/4" thick you will really want to preheat it first and then use 200 amps if not more. This means you will then need a water cooled torch etc. Not cheap...
Finally, when considering repairing anything by welding, ask yourself this question... Why did it break in the first place?????
If it broke as a result of an accident, or misuse, then you might well be able to repair it. If it broke as a result of "normal use" Then the thing was not designed properly in the first place, and so even if you welded repair is PERFECT, The item is doomed to fail again...
Having said all this, i think welding has the best chance of working though, and the worst that can happen is that it will break again!!
I am in fact actually a properly qualified welder, "real" city and guilds and all that, but google "UK Welder" and post a question on there. The members on there are a THOUSAND times more knowledgable where this sort of thing is concerned that i will ever be!!!!
There will no doubt, be more than a few that live fairly closely to you that will actually volunteer to sort this for you, they are a helpful bunch!!
john..
All kinds of things can happen!! For a start you would really need to know the exact composition of the parent metal before you chose a filler wire, as otherwise how are you going to know what the composition of the completed weld will be [you are making a kind of "metal soup"] and what its properties are going to be?
In general though, as long as you know "more or less" what type of aluminium alloy it is, this should not be TOO much of a problem, as there are welding wires that will cope with wide ranges of parent metals, but you will DEFINITELY need to know roughly what "group" of aluminium alloys it belongs to. For example, if it is a magnesium type alloy, as opposed to a aluminium/silicon one, because the the choice of consumables will be completely different. Trouble is there are loads of types and grades of aluminium...
As Sidewinder rightly says, it could very well be [and most likely is] a solution treated and precipitation hardened alloy [don't ask!!] but, if it is, unless you know exactly what the material is, and are able to re-heat treat it, you will end up with a softened/weakened area in the "heat affected zone" next to the weld. This MIGHT actually sort its self out, as SOME alloys "age" at room temperature, and harden/strengthen themselves, all by themselves!! over a few days, others need the heat treatment.
Once again, never mind the "heat affected zone" you have no idea what is going to happen to the weld itself, as unless you know the composition of the parent metal, the composition of the filler rod, and the degree of "dilution" in the weld pool [and are also a metallurgist] god only knows what the result will be!!
This is probably taking a very pessimistic view though, as aluminium alloys are welded every day with great success, but you will definitely have to know at least roughly what alloy it is..
As to welding sets..
You can oxy/acetylene weld aluminium, trouble is the flux is very corrosive and so you cannot do lap joints or fillets as you will not be able to remove all the flux residue and it will later on eat its way through the joint!!
You can MIG weld aluminium, but this is certainly not the way to go for repairs and is really only suitable for the fabrication of such things as tipper lorry bodies.
MIG power sources and TIG power sources by the way are COMPLETELY different. A TIG power source, is very much like a MMA [stick welding] one, in that it is a "constant current" powr source, and has what is called a "sloping characteristic"
This means that it is designed so that, as the welder, [the man doing the welding] lengthens or shortens the arc, although the volt drop across the arc will obviously change, the set does its best to maintain the same current, despite the change in the resistance across the arc gap.
A MIG power source is completely the reverse and is known as a "constant voltage" power source, with a "flat characteristic" This tries to do the opposite thing, and tries to keep the voltage constant, and the current can do as it likes!! Reason for this, is that with MIG, the welding set itself keeps the arc length constant. [it is termed a "semi automatic" process]
It does this by keeping the same voltage across the arc gap. If the gap shortens, the set will increase the current, the wire will melt off quicker, and the original arc length will be restored, and in the same way, if the arc length, well, lengthens! the set will reduce the current, the melting rate of the wire will reduce, and the arc length will once again return to "normal" THE WIRE SPEED REMAINS THE SAME. [With VERY rare exceptions]
In fact, the controls on the front of a MIG set have nothing at all to do with the current, they set the VOLTAGE [and hence the arc length and the "metal transfer mode" [don't ask!]
You actually set the CURRENT by means of the wire feed speed...
Back to TIG, this is, despite what everyone thinks, quite an easy process. If you can gas weld, you can TIG weld, it is as simple as that. Exactly the same technique, just the torch and rod angles are a bit different.
To TIG weld aluminium you need a set with an AC output. [Aluminium HAS been welded on DC in the past in highly specialised applications, but in general, NO CHANCE!!] You also really want "balance control" and "pulse" is nice too!
As to shielding gas, you will need in general, pure argon, [not cheap!] You CANNOT use the same stuff you would use for welding steel with your MIG set.
The main thing that is surprising when you try to weld the stuff though, is the sheer amount of heat that is required. Although aluminium melts at a low temperature, [about 600c??] it makes a great "heat sink" and to weld stuff only about 1/4" thick you will really want to preheat it first and then use 200 amps if not more. This means you will then need a water cooled torch etc. Not cheap...
Finally, when considering repairing anything by welding, ask yourself this question... Why did it break in the first place?????
If it broke as a result of an accident, or misuse, then you might well be able to repair it. If it broke as a result of "normal use" Then the thing was not designed properly in the first place, and so even if you welded repair is PERFECT, The item is doomed to fail again...
Having said all this, i think welding has the best chance of working though, and the worst that can happen is that it will break again!!
I am in fact actually a properly qualified welder, "real" city and guilds and all that, but google "UK Welder" and post a question on there. The members on there are a THOUSAND times more knowledgable where this sort of thing is concerned that i will ever be!!!!
There will no doubt, be more than a few that live fairly closely to you that will actually volunteer to sort this for you, they are a helpful bunch!!
john..
john,
Something else we have in common then as well as living in God's country we both are qualified welders, mind I have not worked as a full time welder for many years now, but have kept my hand in doing repair works.
Something else we have in common then as well as living in God's country we both are qualified welders, mind I have not worked as a full time welder for many years now, but have kept my hand in doing repair works.
Hi Sidewinder, been meaning to PM you for days, not been too well though, try to later!!
john..
john..
